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Drill Stem Testing (DST):

Drill Stem Testing (DST) 2

Objectives::

Objectives: Understanding of DST Tools used in DST General considerations of DST Advantages/Disadvantages of DST Summary 3

Drill Stem Testing:

Drill Stem Testing Drill Stem Test (DST) is used primarily to determine the fluids present in a particular formation and the rate at which they can be produced. A temporary well completion to gather information on the potential productivity of a formation . 4

Slide 7:

REASONS TO DO A DRILL STEM TEST Despite the tremendous value of Core Analysis and Well logging some doubt always remains concerning the potential productivity of an exploratory well .

Slide 8:

KNOWLEDGE + RISK LOW HIGH KNOWLEDGE vs RISK

Slide 9:

REASONS TO DO A DRILL STEM TEST WE NEED TO KNOW : IF THERE IS A RESERVOIR WHAT DOES IT CONTAIN AT WHAT RATE WILL IT PRODUCE FOR HOW LONG WHAT FACILITIES WILL BE REQUIRED AND WHEN WHAT HAZARDS ARE THERE

Slide 10:

Although the cost of such detailed testing is quite high, it is much better to test and be sure, rather than miss a productive zone. Drill Stem Testing (DST) is usually applied to open holes. 10

Points of Particular Importance:

Condition of the hole:

Condition of the hole The close tolerance between the hole and the tool assembly requires a clean well bore if the tool is to reach bottom in an undamaged, unplugged condition The drilling mud should be conditioned to the desired density and viscosity before the test is started 17

Pressure surges:

Pressure surges The pressure effects of pipe movements are of fundamental importance. Special consideration should be given to pipe running and pulling speeds to avoid undue bottom hole pressure variations 18

Operating conditions:

Length and location of the test section Packer seat location Size and number of packers Choke sizes Use of cushions Length of test Handling of test production at the surface Operating conditions 19